Download SKINNING and DISSECTING

SKINNING and DISSECTING
The term “dissection” means more than just cutting your specimen apart. It is a refined method
of seeking, exposing, identifying, and studying internal anatomy. It helps bring into view many
structures not normally seen.
You will not be using a scalpel because you are new to dissection and therefore you will damage
the underlying tissue that is needed for later study. Instead you will rely more heavily upon the
dissecting probe, scissors, and even your fingers. This technique will be demonstrated by your
teacher. Dissection is an art. Anyone can butcher a specimen.
In order to protect yourself from the effects of the preservative, you may wear disposable gloves.
Line the dissection pan with paper towels to absorb excess fluids. These can also be used after
the dissection to wrap the rat before returning it to the plastic bag. Close the bag tightly to keep
the rat from drying out when done at the end of the class period.
To begin the dissection, place the rat ventral side up on the dissecting tray. Before looking at the
muscles and internal organs, it will be necessary to skin the rat. To do this, lift a small flap of
skin in the lower abdominal region. Pinch it together and make a small incision with the
scissors. Slide the point of one scissor blade into the incision. Cut the skin in an anterior
direction while keeping the tip of the scissor blade away from the abdominal cavity. Do not cut
the muscles or puncture the abdomen. Stop the cut at the throat region. Make cuts in a lateral
direction as noted in the diagram below. Gently peel the skin away from the underlying muscle
by tearing the connecting tissue or fascia with a blunt object (fingers or back of the scissors
blade). You will recognize fascia as thin, transparent tissue. Gradually skin the entire rat so that
only “mittens” are left on the appendages. Keep the skin as an additional means of keeping the
rat moist during storage.
YOU NEED TO REMOVE THE ENTIRE HIDE OF THE RAT IN ONE PIECE!